Why You NEED TO REPLACE Original brake lines w/pics

How many times have we heard this:

"why do I need to replace my brake lines, they look fine?"

Why indeed.

FIRST REASON: YAMAHA said they were only supposed to last FOUR YEARS. Four. Not thirty.

Check your date codes.

Sometimes they're easy to see:




Sometimes you really have to look (this one says 5/82)




EVEN MORE IMPORTANT REASON:

I "sectioned" a couple of old lines (12/80 and 5/82) to see exactly what we're dealing with.

There is an outer rubber sheath, then a layer of metallic-appearing (but it's NOT) woven cloth (nylon?) then the red rubber outer-inner hose, with a woven layer fused between it and the black inner liner. That part won't peel apart, it's bonded/molded together.




NOW LET'S EXAMINE THEM MORE CLOSELY. See pic below.

Note that in the hose on the left, you can see the inner black hose cracking and crumbling away. It's even more frightening under a magnifying glass, I think the Canon got a good look though.

Note that in the hose on the right, there is a readily visible SPLIT in the inner hose.

CRACKING, CRUMBLING AND SPLITTING OF THE INNER HOSE:




DOES ANYBODY NEED ANY MORE CONVINCING? I got more old brake hoses I can cut up...

Besides, stainless lines are sexy...



C'mon, people. Just because you can't readily SEE the problem, it's there.

Replace your hoses. You can get original-type hoses if you don't want to upgrade to stainless; but replace your old hoses. With NEW ones.

 

Fitz, another phenomenal write up. Good job getting the cracks on the inside on film. Can tell that is not the easiest thing to do.

That first inner layer looks to be nylon braid. Looks just like marine dock line. Which if exposed to moisture can break down as well. So any cracks on the outside could potentially break that down as well.

Really glad someone finally did this. I was thinking of doing it to mine once I got them off the bike to just see. Did you by chance split one down lengthwise to see the whole of the damage? that would be interesting I think, although possibly hard to do with all the layers in there.

Great write up Fitz!

 

Great job Fitz !! I've been looking for a brake thread to add to my "New Here" warnings - now just add some nasty caliper shots !

 

Thanks! I'll try splitting one (or at least a section of one) lengthwise. The cracking and crumbling for sure goes on up inside the hose as far as a flashlight can see; but the camera just refused to cooperate on focusing into a "black hole."

It took me about 3 dozen shots to get one good one; the faded date code was nearly as difficult.

The fact of the matter is, even though they look "fine" on the outside, bad things have happened on the inside.

I don't think Yamaha intended a 26-year "built-in margin" of safety. Ten years instead of 4, maybe; but not 30.

 

Time, I have some pictures that I took of the Caliper and the MC as I took them apart this winter. If you want I can post them up. Don't want to hijack Fitz's Thread here thou.

 

Start a new one here in "FAQ Suggestions" and call it "why you need to rebuild your caliper and M/C w/pics."

Let's keep this one about brake lines; but I welcome anybody else that has deteriorated brake line pics to add those here.

 

Thanks Fitz
I replaced the lines of my '77 XS650 a few years ago with braided SS lines, I wonder if I kept the original ones on a shelf...if so I will split a few sections, will take pictures and will post them here for sure.

I hope my camera will not challenge me too much!

Edit: no luck, I probably throw them in the garbage can! But I will split the ones off of my Seca 900 when I replace them.

 

Switching to new brake lines is likely to be the biggest improvement in handling you will ever experience on your XJ, esp. if you put in Stainless Braided ones.

You can rejet, tune, get grippy tires, even replace shocks....but a good stop is something you notice!

 

Is there a time when even stainless brake lines need to replaced?

 

They're Teflon wrapped in Stainless Steel covered in PVC.

I'd give them 10 years, then take them somewhere and have them hydrotested. If they're good, another 10 years.

None of those 3 things are subject to much deterioration. Of course you should inspect them regularly.

 

There are different styles of braided lines.

The better ones are as day7a1 says, Teflon wrapped in Stainless Steel covered in PVC. Those should last close to forever.

The other ones are the ones that have the steel braiding, but not the PVC jacket. Those I would pay closer attention to, since the braiding can retain liquid. There is no telling what might get in there and how it might affect the hose inside, so I'd check those periodically for soft spots.

 

OMG ... bigfitz ... I just checked my hoses ... 6/83 ... I'm grounding myself!
Help ... LEN!!

 

Not that I want to minimize the consequences of cracked brake lines on performance and rider's safety, but it came to my mind that I've seen number of times badly cracked intake boots that were not leaking at all.

I know that there is no fluid pression in intake boots, so it is hard to compare, but brake lines are multi-layered exactly to make them stronger, so I tend to think that as long as the outer rubber shell is good, it would prevent the inner rubber layer to blow out.

I may be wrong, it happens all the time...

 

The lines I cut open are crumbling badly enough that they could introduce little "crumbs" of rubber into the system.

Yamaha said they were supposed to last FOUR YEARS. Apparently they knew they wouldn't last oh, say... 30 years?

 

I clearly understand that.

I have to ask: were these lines off of a running bike or have they been drying on a shelf for years before you decide to cut them in pieces? SOme carbs parts can shrink badly when not in use, couldn't it be the same for brake lines?

 

I ran into a problem with my XS where the rubber crumbs plugged the little hole in the master cylinder, which caused my brake to not release sometimes. This required a complete rebuild of everything to clean the crud out.

Floaters in your hydraulics are not a good thing.

 

I took my brake lines off of a running bike that had seen daily use. There were tiny bits of what I assume to be the inner hose that came out when I removed the lines. I have personally experienced the consequences of hydraulic hoses failing due to age (thankfully it as on a piece of stationary machinery). It's very difficult to tell that the hose is old unless you look at the build date. It's true that rubber that has sat out in the weather will show cracking over time, but that happens long after the interior of the lines have began to degrade.

 

I'll definitely cut the hoses, and "expose" the results .. The brake hose thing also happened on my MG .. I was driving it, made one brake application and the brakes locked ... particles from old lines clogged the return path of the fluid, heated, expanded ... well you get the picture.

 

The way I see it, particles or tiny bits of inner hose are more to worry about then the hose itself to blow out. When they make your brakes lock up, that aint funny.

 

Both came off "running" (but not that I'D RIDE) bikes. Max time on shelf: 3 years for one set, four for the other. Does it make a difference if they sat empty on the bike or empty on the shelf for a couple more years? Shall I go cut up the lines off my 650, which is still together? They're probably worse.

Why is it so hard to believe that 30 year old brake lines just might not be viable any more? Did Yamaha miss something?

Brake shoes delaminate. I'm 3-for-3 on my XJs with that one. Shall we debate that too?

THIRTY YEAR OLD BRAKES ARE DANGEROUS.

Period. Not a point of argument, a fact.

I simply posted some proof for those who don't believe in using NEW, "store-bought" parts for certain things. Some things can't be short cut.